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INTERNET DRAFT F.D. Wright, Lexmark International
<draft-wright-ipp-req-00.txt>
November 27, 1996 Expires: May 27, 1997
Requirements for WEB Browser-based Internet Printing
STATUS OF THIS MEMO
This document is an Internet-Draft. Internet-Drafts are working
documents of the Internet Engineering Task Force (IETF), its
areas, and its working groups. Note that other groups may also
distribute working documents as Internet-Drafts.
Internet-Drafts are draft documents valid for a maximum of six
months and may be updated, replaced, or obsoleted by other
documents at any time. It is inappropriate to use Internet-
Drafts as reference material or to cite them other than as ''work
in progress.''
To learn the current status of any Internet-Draft, please check
the ''1id-abstracts.txt'' listing contained in the Internet-
Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net
(Europe), munnari.oz.au (Pacific Rim), ds.internic.net (US East
Coast), or ftp.isi.edu (US West Coast).
1. ABSTRACT
This document describes the requirements for WEB browser-based
Internet printing protocol. It describes the end-user, operator
and administrator wants and needs in the context of printing
documents from a variety of sources. These sources include
standard desktop applications (e.g. word processors,
spreadsheets, and browsers), documents selected by reference
(e.g. URL) and documents created by batch or background
applications. Additionally, requirements for light-weight
printer status and management and job status and management
services will be discussed.
2. TERMINOLOGY
Internet Printing for the purposes of this document is the
application of World Wide Web tools, programs, servers and
networks to allow ''end-users'' to print to a remote printer
using, after initial setup or configuration, the same methods,
operations and paradigms as would be used for a locally attached
or a local area network attached printer. This includes the use
of HTTP servers and browsers for providing static, dynamic and
interactive printer locating services, user installation,
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INTERNET DRAFT Internet Printing Requirements Nov 27, 1996
selection, configuration, and status inquiry of remote printers
and jobs.
For the purposes of this document, a WEB Browser is software
available from a number of sources including but not limited to
the following: Microsoft Internet Explorer, NCSA Mosaic, Netscape
Navigator, Sun Hot Java!. The major task of these products is to
use the Hypertext Transport Protocol (HTTP) to retrieve,
interpret and display Hypertext Markup Language (HTML).
Throughout this document, 'printer' shall be interpreted to
include any device which is capable of marking on a piece of
media using any available technology. No assumption is made
about multi-tiered printing solutions involving servers (single
or multiple) logically in front of the actual printing device and
all such configurations shall be supported but shall appear to
the ''end-user'' as only a single device.
3. REQUIREMENTS
The next three sections identify the requirements of a Web-based
Internet printing protocol from three roles assumed by humans:
''end-user'', ''operator'', and ''administrator.'' The
requirements defined here are only those that need to be
addressed by an application level Internet printing protocol.
Other requirements, such as that the ''operator'' needs physical
access to the printer are not covered by this document.
3.1 End-user
An ''end-user'' of a printer accepting jobs through the Internet
is one of the roles in which humans act. The ''end-user'' is the
person that will submit a job to be printed on the printer.
The requirements of the ''end-user'' are broken down into six
categories: finding/locating, local instance, viewing printer
status, submitting a print job, viewing job status, altering the
print job.
3.1.1 Finding or locating a printer. ''End-users'' wants to be
able to find and locate printers to which they are authorized to
print. They want to be able to perform this function using a
standard WEB browser. Multiple criteria can be applied to find
the printers needed. These criteria include but are not limited
to:
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- by name (Printer 1, Joes-color-printer, etc.)
- by geographic location (bldg 1, Kentucky, etc.)
- by capability or attribute (color, duplex, legal paper, etc.)
Additionally, ''end-users'' want to be able to limit the scope of
their searching to:
- inside the corporate firewall
- include only a particular domain (lexmark.com)
- exclude specified domains
3.1.2 Create an instance of the printer. After finding the
desired printer, an ''end-user'' needs to be able to create a
local instance of that printer within the ''end-user'' operating
system or desktop. This local instance will vary depending upon
the printing paradigm of the operating system. For example, some
UNIX users will only want a queue created on the machine while
other UNIX users and Windows NT users will want not only the
queue but also the necessary icons and registry entries to be
created and initialized. Where required, drivers may need to be
downloaded from some repository and installed on the computer.
All necessary decompressing, unpacking, and other installation
actions should occur without ''end-user'' interaction or
intervention excepting initial approval by the ''end-user.''
Once the local instance of the printer has been installed, it
shall appear to the ''end-user'' of operating system and to the
applications running there as any other printer (local, local
area network connected, or network operating system connected) on
the ''end-user'' desktop or environment.
3.1.3 Viewing the status of a printer. Before using a selected
printer or, in fact at any time, the ''end-user'' needs the
ability to verify the characteristics and status of both printers
and jobs queued for that printer using the WEB browser. When
checking the characteristics of a printer, the ''end-user''
typically wants to be able to determine the capability of the
device, e.g.:
- loaded media, commonly paper, by size and type
- paper handling capability, e.g. duplex, collating, finishing
- color capability
When checking the status of the printer, the ''end-user''
typically wants to be able to determine:
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- is the printer on-line?
- what are the defaults to be used for printing?
When checking the status on jobs queued for the printer, the
''end-user'' typically wants to be able to determine:
- how many jobs are queued for the printer?
- how are job priorities assigned?
3.1.4 S ubmitting a print job. Once the desired printer has been
located and installed, the ''end-user'' wants to print to that
printer from normal applications using standard methods. These
normal applications include such programs as word processors,
spreadsheets, data-base applications, WEB browsers, etc. In
addition to printing from an application, the ''end-user'' needs
to have the ability to submit a print job by reference. Printing
by reference is defined to mean using a WEB browser to submit a
job by providing a reference to an existing document. The
reference, which could be a URL, will be resolved before the
actual print process occurs.
Some means shall be provided to determine if the format of a job
matches the capability of the printer. This can either be done
automatically by the printer or can be done by the ''end-user.''
A standard action shall be defined should the job's requirements
not match the capabilities of the printer.
Because the ''end-user'' does not want to know the details of the
underlying printing process, the protocol must support job-to-
printer capability matching (all implementations are not
necessarily required to implement this function.) This matching
capability requires knowing both the printer's capabilities and
attributes and those capabilities and attributes required by the
job. Actions taken when a print job requires capabilities or
attributes that are not available on the printer vary and can
include but are not limited to:
- rejecting the print job
- redirecting the print job to another printer
- printing the job, accepting differences in the appearance
Print jobs will be submitted by background or batch applications
without human intervention. Any application level Internet
printing application must support this type of printing.
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''End-users'' need the ability to set certain print job
parameters at the time the job is submitted. These parameters
include but are not limited to:
- number of copies
- job priority
- job defaults
3.1.5 Viewing the status of a submitted print job. After a job
has been submitted to a printer, the ''end-user'' needs a way to
view the status of that job (i.e. job waiting, job printing, job
done) using a WEB browser.
In addition to the need to inquire about the status of a print
job, automatic notification of the completion of that job is also
required. This notification capability is not defined by the
protocol but the protocol must provide a means of enabling and
disabling the notification.
3.1.6 Altering the status of a submitted print job. While a job
is waiting to be printing or has been started but not yet
completed, the original creator/submitter of the print job (i.e.
the ''end-user'') shall be able to cancel the job entirely (job
is waiting) or the remaining portion of it (job is printing.)
3.2 Operator
An ''operator'' of a printer accepting jobs through the Internet
is one of the roles in which humans act. The ''operator'' has
the responsibility of monitoring the status of the printer as
well as managing and controlling the jobs at the device. These
responsibilities include but are not limited to the replenishing
of supplies (ink, toner, paper, etc.), the clearing of minor
errors (paper jams, etc.) and the reprioritization of ''end-
user'' jobs.
The requirements of the ''operator'' include all those of the
''end-user.''
3.2.1 Alerting. One of the required ''operator'' functions is
having the ability to discover or to be alerted to changes in the
status of the printer particularly those changes that cause the
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INTERNET DRAFT Internet Printing Requirements Nov 27, 1996
printer to stop printing and to be able to correct those
problems. As such, an Internet printing protocol shall be able
to alert a designated ''operator'' or ''operators'' to these
conditions such as æout of paperÆ, æout of inkÆ, etc.
Additionally. the ''operator'' shall be able to, asynchronous to
other printer activity, inquire as to the printer or job status.
3.2.2 Changing Print and Job Status. Another of the required
''operator'' functions is the ability to affect changes to
printer and job status remotely. For example, the ''operator''
will need to be able to reprioritize or cancel any print jobs on
a printer to which the ''operator'' has authority.
3.3 Administrator
An ''administrator'' of a printer accepting jobs through the
Internet is one of the roles in which humans act. The
''administrator'' has the responsibility of creating the printer
instances and controlling the authorization of other
''end-users'' and ''operators.''
The requirements of the ''administrator'' include all those of
the ''end-user.'' Additionally the ''administrator'' must have
tools, programs, utilities and supporting protocols available to
be able to:
- create an instance of a printer
- create, edit and maintain the list of authorized ''end-users''
- create, edit and maintain the list of authorized ''operators''
- create, edit and maintain the list of authorized
''administrators''
- create, customize, change or otherwise alter the manner in
which the status of printers and jobs are presented
- create, customize, change or otherwise alter front-end or
pre-print processes
- create, customize, change or otherwise alter back-end or
post-print processes
- administrate billing or other charge-back mechanisms
- create sets of defaults
- create sets of capabilities
The ''administrator'' must have the capability to perform all the
above tasks locally or remotely to the printer.
4.0 OBJECTIVES OF THE PROTOCOL
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INTERNET DRAFT Internet Printing Requirements Nov 27, 1996
The protocol to be defined by an Internet printing working group
will address the requirements of the ''end-user''. It will not,
at least initially, address the ''operator'' or ''administrator''
requirements.
The protocol defined shall be independent of the operating system
of both the client and the server. Any platform providing a WEB
Browser shall be supported as a client. Any platform providing a
WEB/HTTP server and printing services shall be supported as a
server.
4.1 Security
There are general requirements for security in an Internet
printing application. These requirements include authentication,
authorization, privacy, and commercial transaction.
4.2 Interaction with LPD (RFC1179)
Many versions of UNIX and in fact other operating systems provide
a means of printing as described in RFC1179 (Line Printer Daemon
Protocol.) This document describes the file formats for the
control and data files as well as the messages used by the
protocol. Because of the simplistic approach taken by this
protocol, many manufacturers have include proprietary
enhancements and extensions to 'lpd.' Because of this divergence
and due to other requirements described in this document, there
is no requirement for backward compatibility with 'lpd'.
4.3 Firewalls
As stated in the ''end-user'' requirements section, Internet
printing shall by definition support printing from one enterprise
to another. As such, the Internet printing protocol must be
capable of passing through firewalls (where enabled by the
firewall administrator) preferably without modification to the
existing firewall technology.
4.4 Internationalization
Users of Internet printing will come from all over the world. As
such, where appropriate, internationalization and localization
will be enabled for the protocol.
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INTERNET DRAFT Internet Printing Requirements Nov 27, 1996
5.0 REFERENCES
RFC1179 - Line Printer Daemon Protocol
RFC1759 - Printer MIB
ISO/IEC 10175, Document Printing Application
6.0 ACKNOWLEDGMENTS
This document draws heavily from preliminary work done by others.
The author gratefully acknowledges the contributions of:
Scott Isaacson
Novell
scott_isaacson@novell.com
Roger Debry
IBM
rdebry@us1.ibm.com
Carl-Uno Manros
Xerox
manros@cp10.es.xerox.com
7.0 AUTHOR'S ADDRESS
F.D. (Don) Wright
Lexmark International
C14/035-3
740 New Circle Rd
Lexington, KY 40511
Phone: 606-232-4808
Fax: 606-232-6740
E-mail: don@lexmark.com
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